This project is directed at testing the hypothesis that diabetic sural nerve water represents a marker for increased aldose reductase flux, as an early and reversible step in the pathogenesis of diabetic neuropathy. We plan to administer an inhibitor of AR, Tolrestat, in a double blind fashion to 20 diabetic subjects with elevated nerve water and early neuropathy, and to follow the nerve water and neuropathy with MRI and neurophysiology testing to determine both the validity of the hypothesis & utility of AR inhibition as a therapy.